Nitrogen base and method of making same



Patented July 10, 1934 PATENT OFFICE 1,9653%, NITROGEN BASE sign METHOD or MAKING Denis L. Fox, Berkeley, cam. asslgnout'o Standard Oil Company 01' California, San Francisco,

Calif., a corporation of Delaware No Drawing. Application March 2, 1929,

Serial No. 344.098

11 Claims.

- This invention relates to the recovery of nitrogen compounds from oil and particularly from hydrocarbon oils such aspetroleum.

It is well' known that most pertoleum oils,

5 shale oils andsimilar hydrocarbon oils contain nitrogen compounds in various quantities. It has been known that these nitrogen compounds 'could be extracted, in part at least, from the oils by means of dilute sulphuric acid or other mineral acids I haveals'o found that extracts obtained by treating oils with liquid sulphur dioxide contain a complex mixture of nitrogen compounds of varying strengths as bases, some of said compounds even appearing to be neutral.

From this it may be seen that the stronger the acid used in the extract of nitrogen compounds, 'the larger will be the quantity of nitrogen bases removed, but even with the strongest acids there i are nitrogen compounds weakly basic or neutral 0 which are not removed.

object of this invention is to disclose and provide a process of removing and separating nitrogen compounds from oils.

Another object. is to disclose and provide a process of extracting and removing nitrogen bases from petroleum oils.

Another object is to disclose and provide a. process of obtaining nitrogen bases in relatively the oil bodies orimpurities. When oils are treated .with-sulphur trioxide or with liquid sulphur di-' pure condition from petroleum-oils.

A still further object is to disclose and provide a method whereby nitrogen compounds and bases may be completely removed from oils in a relatively pure condition.

"Another object of this invention is to provide "nitrogen bases and compounds in concentrated "form. l A still further object is to provide, as an article ,of manufacture, nitrogen bases of particularly desirable characteristics.

An-object of this invention is to provide, as an article of manufacture, mixtures; of nitrogen bases having particularly desirable properties.

The nitrogen compounds occurring in most petroleum oils, shale oils and the like are volatile 5 at the temperatures employed in distillation, and consequently they may be found in the distillates.

I have discovered that all, or nearly all, of th'e nitrogen bases in cracked petroleum distillates arev of] relatively low molecular weight and are 5 stronger in general, as bases, than thoseoriginaily occurring in petroleum. v I

These compounds, or bases may be removed completely, or nearly so, by means of dilute acid solutions. I r When'liquid acids are used such as liquid sulpetroleum oils containing nitrogen com- 'phur dioxide and concentrated sulphuric acid, however, large amounts of oil bodies are also extracted from the oil and difficulties are encountered in separating the extractednitrogen compounds from the oil bodies; Furthermore, when aqueous acid is used, all of the acid in the water can not be made to combine with the nitrogen bases because of the hydrolysis of the resulting salts and consequent resolution of the bases in the oil. When aqueous acids are used, as much as one hundred per cent excess of acid is required in some cases to hold the bases in the water solution as salts, and this excess is all wasted since, in order to obtain the free bases, all

of the acid must be neutralized. By carrying out the extract in accordance-with the process embraced by this invention, all of the disadvantages recited hereinabove areobviated. I have discovered that the nitrogen compound present in oils can be more readily removed-by the use of gaseous acids such as hydrogen chloride or sulphur dioxide, than by the use of liquid acids such assulphuric acid or liquid sulphur dioxide. By using gaseous reagents it is possible to extract the nitrogen compounds without removing oil bodies or impurities and therefore a subsequent separation is not required for the separation of the nitrogen compounds from so intimately mixed with and included with the impurities that it is impractical to separate them from the oil bodies. As has been stated above, hydrolysis of nitrogen base salts occurs when acid solutions are used for extraction, but when an anhydrous acid in gaseous state is used, in accordance with this invention, no water is present, and consequently no hydrolysis of the salts formed occurs. A great saving in acid is made possible by this process in that no excess of acid is required beyond that needed to combine with the bases. l,

Furthermore, by employing acid in the anhydrous state, the nitrogen bases obtained directly as relatively pure salts and not in the- :form of dilute. aqueous solutions. greatly reduces the volume of material to be handled. If an aqueous solution saturated with sulphur dioxide is employed, it is so weak that only a small proportion of the is removed from an oil.

I have also found that distillates obtained by pounds are particularly suitable as sources of nitrogen compounds or as raw material for use in my process.

Any suitable apparatus may be employed in carrying out the process described herein, and I am not to be limited to any particular form of apparatus. The process may be carried out either by the batch method or by a continuous counterflow method. Apparatus for use in counterflow methods is well known in the art and the arrangement of various well known units so as to carry out the process does not of itself involve invention.

The oil to be treated in accordance .with the process of this invention may be placed in an agitator or other suitable receptacle and anhydrous acid, or acid anhydride in gaseous form, then bubbled through the oil at moderate temperatures, or temperatures somewhat lower than those ordinarily employed. Sulphur dioxide or hydrogen chloride may be employed. As stated hereinabove, the desired contact between the gaseous acid and the oil may be accomplished by counter-flow methods if desired. The treatment with acid is continued until the acid gases have reacted with all, or substantially all, of the nitrogen bases present therein. Most of the nitrogen bases are precipitated by the action of the acid gas in the form of salts o nitrogen bases and may be separated from the residual oil by sedimenta tion, filtration or other methods.

When cracked naphtha is used as the oil stock in accordance with this process, it has been found that'only about 0.007 pound of hydrogen chloride gas and/or about 0.008 pound of sulphur dioxide per gallon of naphtha is necessary to effect the extraction of substantially all the nitrogen bases present in such naphtha. These quantitles are merely illustrative and will vary with the character of the oil being treated, from about 0.002 pounds to 0.008 pounds of hydrogen chloride or sulfur dioxide per gallon.

A certain proportion of the salts of nitrogen bases remains in solution or suspension in the oil and suchsalt may be recovered separately, by extraction with an aqueous solvent. For example, the salts remaining in solution or suspension in the oil, being water soluble may be removed from the oil by extraction with water. The salts may be used directly in theform of a water solution or they may beneutralized with alkali so as to precipitate the nitrogen bases.

The salts of nitrogen'bases which are precipitated from the oil by treatment with a gaseous acid, or acid anhydride, may be used as such or they may be neutralized to form nitrogen bases. The products obtained by this process are complex mixtures of nitrogen bases and it has been discovered that these bases and salts thereof have toxic properties which make them particularly useful in the preparation of insecticides. The nitrogen compounds and bases prepared in accordance with this invention may be used in the form of the solution of the salts in water or as a solution of the free bases in oil or an emulsion of bases in oil and the salts in water or the nitrogen bases may be embodied in a dust or powder.

Obviously these toxic salts and bases when used for insecticidal purposes may be used alone ortogether with other ingredients and insecticides.

While the process has been described as being applied to petroleum oils, it is to be understood that the process is also applicable to other nitrogen-bearing hydrocarbon oils and is not limited to the particular details described herein, but embodies all the changes and modifications which come within the scope of the appended claims.

I claim:

, 1. A process of recovering nitrogen bases from oils comprising treating oil containing nitrogen compounds with substantially dry gaseous sulphur dioxide, without oxidizing the oil to remove impurities therefrom, separating salts of nitrogen bases precipitated from the oil by such treatment, and extracting suspended salts of nitrogen bases from the..treated oil.

2.-A process of recovering nitrogen bases from oils comprising treating a distillate obtained by cracking oil containing nitrogen compounds with gaseous sulphur dioxide to form salts of nitrogen compounds without oxidizing the oil to remove impurities therefrom, separating salts of nitrogen bases precipitated by such treatment from the oil, and extracting suspended-salts of nitrogen bases from the treated oil.

, 3. A mixture of salts of nitrogen bases substantially. free from hydrocarbon oils precipitated from petroleum oils by treating a petroleum oil containing nitrogen compounds with a material selected from the group consisting of substantially anhydrous gaseous sulfur dioxide and hydrogen chloride.

4. In a method of recovering nitrogen bases from petroleum oils, the steps of treating a petroleum oil with a substantially dry gaseous material selected from the group consisting of sulfur dioxide and hydrogen chloride, without oxidizing the oil to removeimpurities therefrom, to

form salts of nitrogen compounds present in said oil, and then separating such salts from' the oil. 5. In a method of recovering nitrogen bases from petroleum distillates, the steps of treating.

a petroleum distillate containing nitrogen compounds with a substantially anhydrous gaseous material selected from the group consisting of sulfur dioxide and hydrogen chloride to precipitate salts of nitrogen bases without'oxidizing the petroleum distillate to remove the impurities therefrom, and separating the precipitated salts of nitrogen bases from the distillate.

6. In a method of recovering nitrogen bases from petroleum distillates, the steps of treating a petroleum distillate containing nitrogen compounds with a substantially anhydrous gaseous material selected from the group consisting of sulfur dioxide and hydrogen chloride to precipitate salts of nitrogen bases without oxidizing the petroleum distillate to remove impurities therefrom, separating the precipitated salts of nitrogen bases from the distillate, and extracting suspended salts of nitrogen bases from the treated distillate. I

7. In a method of recovering nitrogen bases frompetroleum distillates, the-steps of treating a petroleum distillate containing nitrogen compounds with a substantially anhydrous sulfur dioxide in gaseous state to precipitate salts of nitrogen bases without oxidizing the petroleum distillate to remove impurities therefrom,- and separating the precipitated salts of nitrogen bases from the distillate.

8. In a method of recovering nitrogen bases from petroleum distillates, the steps of treating a petroleum distillate containing nitrogen compounds with a substantially anhydrous hydrogen chloride in gaseous state to precipitate salts of nitrogen bases without oxidizing the petroleum distillate to remove impurities therefrom, and separating precipitated salts of nitrogen from the distillate.

9. In a method or recovering nitrogen ba's'es Raw.

compounds precipitated from petroleum oil by treating an oil containing nitrogen compounds with substantially anhydrous sulfur dioxide in I gaseous state.

11. A.mixture of salts of nitrogen bases substantially free from hydrocarbon oils precipitat ed from petroleum oil by treating a petroleum oil containing nitrogen compounds with substan-' tially anhydrous hydrogen chloride in gaseous state.

DENIS L. FOX.

III 

